Simply not true. If Martin was going out of sight of the vehicle, he would have to get out of the car to observe him.
Asking a person what they are doing in an area (which all agree that Zimmerman did) is not trying to apprehend or aggression.
Without having identified himself as the security, Martin could not have known anything other than a perfect stranger was asking him to identify himself.
If a random person, for all intents and purposes from Martin’s POV, came up to you or I asking for our identification, we would’t give it. Especially if that person was asking in an aggressive fashion.